Serena, Sharapova again on Miami collision course

Maria Sharapova reacts during her match against Lucie Safarova (not pictured) on day six of the Sony …

By Steve Keating

MIAMI (Reuters) - Six-times Miami champion Serena Williams and five-times runner-up Maria Sharapova remained on another Sony Open collision course after each recorded fourth-round wins on Monday.

While Williams and Sharapova clashed in last year's final there will be no championship rematch on Saturday at Crandon Park with the American and Russian on the same side of the draw and closing in on a semi-final showdown.

After getting her title defense off to a slow start world number one Williams, who lives an hour's drive from the Crandon Park Tennis Center and considers the event her home tournament, stepped it up a gear against Coco Vandeweghe sweeping past the young American qualifier 6-3 6-1 in 79 minutes.

"I was definitely happier today," Williams told reporters. "I was really struggling my first two matches, so I just wanted to have a better performance today.

"Going into the match I knew I could only do better. That kind of helped out, too."

Maria Sharapova hits a forehand against Lucie Safarova (not pictured) on day six of the Sony Open at …

Fourth seed Sharapova got a much-needed wake-up call after sleep-walking her way through the opening set before dispatching Belgian Kirsten Flipkens 3-6 6-4 6-1.

Former world number one and 12th seed Ana Ivanovic seemed headed for a quarter-final berth after comfortably taking the first set against eighth seed Czech Petra Kvitova but fell apart after that, committing 11 double faults en route to a stunning 3-6 6-0 6-0 loss.

Williams, a minority owner of the National Football League's Miami Dolphins, once again stepped onto the court dressed in her team's turquoise and orange colors and kicked off the match by claiming the only break of the opening set for the early lead.

In the second set, Williams simply blitzed Vandeweghe, overpowering the 22-year-old who managed to hold her serve just once against the 17-times grand slam winner.

"It doesn't feel great (playing bad tennis)," said Williams. "That also gave me confidence to know if I'm winning these matches when I'm playing some of the worst tennis I have personally played in the past couple of years, then, you know, it gave me a lot of hope.

Maria Sharapova celebrates after her match against Lucie Safarova (not pictured) on day six of the S …

"I'm in a better mood now. It was impossible for me to be in a good mood after I played those last matches."

Sharapova, playing the first match of the day on a drowsy and overcast centre court, appeared to have trouble getting up for her fourth-round contest, as did many of the ticket holders with only a few hundred spectators sprinkled across the quiet stadium as play began.

"I started off ... probably looked like it was too early," Sharapova told reporters. "I usually like playing first match on, but I didn't start off the way I wanted to.

"Nothing was working. Just the way it went in the beginning."

Flipkens certainly came ready to play and broke a misfiring Sharapova at the first opportunity and again to go up 4-0 with the help of back-to-back double faults from the Russian.